Contents

History

Aoba and Sei when they were born.

Sei and Aoba were children born with specific genetic engineering from Toue's research labs. Their genes were manipulated to give them natural abilities to control people's will. These powers were based on the theories of Tae, who once worked for Toue on neural research. Sei and Aoba were born with no pigments and they were connected via their hair which had nerves in it. By bad luck, the two of them died having been just born, but fortunately, when the hair connecting them was severed, Sei's breathing returned.

From that moment on, Sei's consciousness was analyzed since he was a child and he only had little time to act on his own. Longing for freedom, Sei created multiple consciousnesses with which he was able to access various networks. Toue used Sei's ability to create personal dolls and injecting Sei's consciousness in them, one of them being Usui, and as a result, Rhyme gained popularity. Having created such a large scale of consciousnesses, Sei's own had diffused rapidly, and gradually became weak.

Sei's power to control people lies in his eyes, which makes him able to give birth to things (i.e. his multiple consciousnesses and dolls like Usui) in contrast to Aoba's power, which is to destroy.

Appearance

Sei, waiting for Aoba in his room.

Sei is often described as "feeble". He is very pale, almost sickly-looking, highly possible due to the constant years of experimenting on his physical and mental being. He adorns long, black hair that reaches down to his neck and black eyes. His build is very slender, but looks to be more broader compared to Aoba's. Despite being twins, Sei's gloomy appearance causes him to look drastically different from his brother, who dresses and looks more lively in comparison.

Sei's outfit consists of a studded, black fedora with a Morphine pin on the side. He wears an open shouldered, long sleeved white shirt that has black straps over his shoulders. He has matching jeans and gloves that have skeletal designs and wears a half skirt that is connected to the right side hem of the pants, connected by black suspenders that hang on either side of his body. Two studded collars adorn both his neck and wrists. He also wears a pair of white boots with black studs.

Sei is also noted for his very androgynous appearance, by both players and even Aoba himself. When Aoba first sees one of Sei's images in an alleyway, he refers to him with the gender-neutral pronouns "they" and "them", implying he could not tell if Sei was male or female at first glance. It was not until Toue's introduction of Sei did Aoba realize he was indeed male.

Personality

When first introduced, Sei seemingly has no interest in others. He acts very distant and has a very dead gaze in his eyes.

However, it's revealed that the reason for his cold exterior is because of years of testing that has deteriorated his physical and mental being. It is not until Aoba is pulled into Sei's mind that the true Sei is shown to be a very kind and soft-spoken person. He's shown to care deeply for Aoba and Ren, his final action proving how much he wanted them to be happy.

Despite being lifeless at first, Sei is almost always seen smiling, even during the destruction of Oval Tower.

Story

Note: Sei does not make any major speaking or physical appearances until Ren's Route.Spoiler alert, so please read on with caution!

Common Route

Sei sends numerous messages and clues to Aoba in the form of an RPG titled Silent Oath, or commonly referred to in-game as its sender, Captive Princess. He also makes a very short appearance by reaching out to Aoba and gently touching his face when Aoba gets caught up in a Rhyme match after his meet up with Mizuki. However, his form is only seen as a blinding, white light, which disappears quickly and confuses Aoba as to what the phenomenon was.

Main Four Routes

During Koujaku, Noiz, Mink and Clear's routes, Sei will send all of them and Aoba an automatic download of Captive Princess which shows the blue knight wandering a dungeon for a treasure chest. However, Aoba will be the only one who finds the chest and receives the invitation to Platinum Jail, which allows visitation for both him and one guest (one of the four love interests).

With the exception of Mink and Clear's routes, Sei will unlock the back entryway for Aoba, Koujaku and Noiz to allow them inside. Aoba will receive a final text message from Sei saying "It has been completely opened." / "The lock to the heart has been opened.". Afterward, if the player is to achieve a good end, Sei will initiate the tower's destruction and multiple holographic computer screens will randomly pop up everywhere with him, smiling (with the exception of Mink's route, in which it is Scratch who helps destroy the tower instead to comply with Mink's plan).

Ren's Route

Aoba first "meets" Sei in an alleyway while frantically searching for the runaway Ren. Sei is slumped over with his head on his knees and as Aoba reaches out to ask if he is alright, Sei looks up at him and a shock runs through Aoba's head. Once he shakes it off, Aoba finds that Sei had vanished instantly.

Toue giving his speech while Sei looks on.

Once back at Glitter, Aoba and Ren plan to go to the announcement Toue will be giving to Platinum Jail's and the Old Resident District's citizens. As they make their way there and observe the speech, Toue introduces Sei, who is standing behind him silently and looking on with little to no interest of the event. Aoba immediately recognizes him as the same young man in the alleyway but begins to find the longer he gazes at Sei, the more he feels his head pounding and anxiety building. Looking around at the other people in he crowd, Aoba realizes it's not just him feeling off about Sei, as they all seem to be instantly infatuated by him as if under a spell.

Later when Aoba breaks into Oval Tower and painfully presses onward, he enters a lab room where there are multiple large test tubes with an orange liquid filling them. Inside are multiple test subjects, some that looked inhuman or disfigured. As Aoba looks around, one of them banged loudly on the glass encasing it and mouthed an inaudible sentence to him. Unable to understand what it was trying to say, Aoba hears a voice relieved that he had finally come and asks for him to destroy him. However, it's then that Aoba is cornered by numerous Morphine members and uncovers that Virus and Trip were the team leaders the whole time.

Virus begins to explain to Aoba his history and reveals that he and Sei are, in fact, fraternal twins. He goes on to tell him how Tae used to work for Toue, their involvement with Mizuki and Dry Juice, and their motives for taking interest in Aoba after taking care of Sei for many years. Virus informs Aoba that Sei is dying and can no longer go on living anymore due to the many of years of being prodded at as a test subject thus causing his mind and body to slowly wither away. As Aoba listens in shock from both the new abundance of information and his former friends' betrayal, he doubts Virus could be making it up and is suddenly pummeled by Morphine due to their orders. Virus and Trip then say that because Toue had Sei, it was only fair that they could keep Aoba (it is here where the choices to achieve Virus and Trip's Bad End are given).

Should the player make the choices to continue Ren's route, Aoba will be saved by his friends. After he uses Scrap on himself and encounters Ren's feelings (the choices to achieve Ren's Bad and Good Ending is here), Aoba makes it up to Toue and is challenged to a Rhyme match with him. Here, it's revealed that Usui is not only Toue's Allmate, but also a doll created using Sei's power.

Proving to be much too powerful for them, Ren suggests Aoba to call out to Sei through Usui since they harbor the same consciousness. Aoba tries and succeeds, able to throw Usui off and allowing Ren to land a finishing blow to her, obliterating her existence as a whole. As Toue admits defeat, he shows Aoba where Sei is residing on the other side of the room. Aoba cautiously makes his way into the room, and finds it to be a colorful one, adorned with stuffed animals and child-like things. In the middle, Sei sits on a large chair, staring blankly. Aoba slowly makes his way up to him and kneels down while gently holding Sei's hands in his, apologizing for being so late. Sei then looks into Aoba's eyes and both are pulled into his consciousness.

Aoba and Ren (in his Rhyme form) find themselves in a blank white space until Sei's figure arrives in front of them. He is s

Sei and the other Aoba confront Aoba and Ren.

hown completely pale white, with black markings decorating his skin and his hair grown out. He tells Aoba this is his true form, back to how they were first born. Sei then informs Aoba that he does not hate Toue for what he had done- he explains that nobody really knows what is right

or wrong, and only the people themselves can make that kind of decision as to what is so. He then reveals that the other Aoba's true motive was to simply be accepted by Aoba instead of being pushed away. As he moves onto Ren, he asks him if he truly wants to protect Aoba and notices that he has become an entirely new existence.

As their conversation nears the end, Sei admits that he has been waiting his whole life to meet his brother and for Aoba to fulfill his wish- to destroy him with his power. Realizing the voice accompanied with the words he's heard many times before, Aoba recognize sthat it was Sei who had been calling out to him and sending him the Captive Princess games. Aoba begins to hesitate, saying that it is too sad for both of them to have just met and now have to part so soon because Sei cannot take the suffering anymore. Sei comforts Aoba and promises everything will be alright because he has Ren now. Through tears, Aoba reluctantly uses Scrap to destroy his brother's mind permanently. Sei thanks Aoba from the bottom of his heart with a smile, and Aoba and Ren are sent back into Aoba's head where they stand on the familiar beach shore with the other Aoba.

After Aoba returns to reality, he finds that the tower collapsing completely while Koujaku, Clear, Noiz and Mink gather around him. Checking to see if Ren is alright, Aoba is shocked to find that his Allmate is back to its original settings and that he can no longer feel Ren inside of him. Confused and devastated, Aoba hugs "Ren" tightly and begins to sob.

A year later, Aoba receives a phone call saying that Sei was admitted and waiting for him in the Old Resident District's hospital from an
unknown caller. As he hesitantly travels to see if it is really him, Aoba receives the final game from Captive Princess. It shows both the princess and knight finally meeting together with a treasure chest showing up in between them. As they jump up and down happily, Aoba wonders what it could mean, closing it out. Walking into the hospital room, he finds that the body of the person is in fact Sei's and calls out to him. When "Sei" opens his eyes, Aoba is surprised to find them a familiar amber color and realizes what Sei had given him as a final present. Beginning to cry, he hugs the newly brought back Ren while whispering a "welcome back", and the game ends.

Relationships

Aoba Seragaki

Sei and Aoba have a very profound brotherly love for each other. While Aoba felt immense guilt that he was the one living his life normally while Sei was locked up, Sei insists that it wasn't his nor Tae's or even Toue's fault. Sei showed immense happiness when he and Aoba finally got to meet but sadly wished that they could have met sooner before Sei's health began to decline. Aoba affectionally calls Sei "big brother" and, while he was in deep anguish for having to fulfill Sei's wish, absolutely wanted him to be at peace and without suffering anymore.

Ren

Sei was aware of both Ren and the other Aoba being separated from Aoba's consciousness, but also recognized Ren had become an individual existence thanks to Aoba accepting his feelings for him and asked him to protect Aoba from then on. Once Oval Tower had collapsed, Sei had sometime transferred Ren's consciousness into his own body afterward, giving him his own physical being in reality. This was Sei's final present for Aoba, as he wished for both him and Ren to be happy together.

Toue

Despite conducting multiple mentally and physically straining experiments and tests since he was born, Toue claimed that Sei was very precious to him, as if he were his own son. Sei did not show any outward emotion towards Toue, but reveals to Aoba that he did not resent him, as Toue had believed he was doing what he thought was right.

Virus and Trip

Virus and Trip claim to have been Sei's caretakers prior to meeting Aoba. Sometime after Oval Tower's destruction, Sei's body was taken by Virus and Trip after realizing he was still alive- only for the two to realize that the person inside of Sei's body was not in fact Sei. Taking interest in the case, they took care of him for a year and sent him to the Old Resident District's hospital. It's revealed in Re:Connect that the "doctor" who called Aoba to go visit his "brother" was, in fact, Virus.

Main Four

While Sei does not interact with Koujaku, Noiz, Mink or Clear, it's shown he is at least aware of each of them being with Aoba as he sends auto downloads of Silent Oath to all of them. The invitation into Platinum Jail also approves of both Aoba and one guest being permitted to enter.

Trivia

Sei is technically the first character to be introduced in the game, as the words being typed are actually him calling out to Aoba:

The same words are repeated when Aoba walks into the lab room filled with test subjects in large tanks.

In the main four routes after the tower collapses, Aoba informs the player that Usui is no longer used after the Rhyme companies had been revamped from Toue Inc., however the reason as to why is unknown. In Ren's Route, it's shown that because Ren had defeated Usui in Rhyme, her existence was obliterated completely, which also harbored a large part of Sei's consciousness and power. It is possible that Sei had died in the main four routes from either the tower's collapse or natural causes due to his health, thus erasing her in the process and being unable to be used for future Rhyme games, though it is not confirmed.

Sei's name could be derived from the Japanese kanji 生 which has an on-yomi reading of sei. The kanji itself means "life" or "birth," appropriate for his ability to give life to dolls that harbor a part of himself in them -as Toue states in his final meeting with Aoba in Ren's route.